Strap for Seamaster Diver 300M Master Co-Axial 42 Swiss Armed Forces

The lug width is 20mm. Measure the distance between the case attachment pins at the lugs to verify compatibility with aftermarket straps. A 20mm strap will fit perfectly without lateral play, ensuring a precise interface between the leather and the stainless steel case.

The choice depends on intended use. For elegance: black or brown alligator with vegetable tanning; for diving and water: blue or black-grey NATO with technical fabric; for daily balance: cognac calf with vegetable tanning and grey linen inner lining. Each material highlights different aspects of the watch.

Use a pin remover to gently push the pins from the opposite side, freeing the lug from the case. Align the new pins with the holes in the strap and reinsert into the case. Ensure the strap is compatible with the 20mm lug width to avoid lateral play.

A leather strap with vegetable tanning lasts 3-5 years if worn daily and subjected to regular maintenance (cleaning, conditioning). The patina develops progressively over the first year. Moisture accelerates aging; an inner technical fabric lining extends the useful life.

Yes, all straps with 20mm lug width are compatible. Always verify the width before purchase using a digital caliper on the original case. Milanostraps offers artisanal customizable straps for this size with premium leathers and custom finishing.